Generally, coating resins are insoluble in water. Therefore, in general practice they have been dissolved in a suitable organic solvent or dispersed in water with the aid of an emulsifying or surfactant agent in order to provide a coating composition suitable for application to a substrate surface. A serious disadvantage of organic solvent solutions is that they are potentially toxic, flammable, and environmental pollutants.
Water reducible coatings do not present these problems and are, therefore, highly desirable. For this reason it is expected that water reducible coatings will have a major share of the coating market in the future.
Many techniques are known for the production of latices for water reducible coatings but various difficulties are encountered with each of these techniques. For instance, it has been impossible to "scale up" many of these techniques to levels needed in actual commercial production. Instability of latex particles is a problem that has also often been encountered. For example, instability of latex particles can result in paint solidifying in its can before use. It is also desirable to produce a latex with large particle size. Many of the techniques presented in the prior do not accomplish this goal.
The present invention can be scaled up to a level needed for actual commercial production and produces stable large particle size latices. An additional benefit realized by using this invention is that substantially more latex can be produced in a given production facility.